And how much time is gained in reading tags compared to bar codes?
There are various types of RFID systems, each of which can store a different amount of data, which affects the amount of time required to read a tag. But since you mentioned bar codes, I will assume you are asking about passive RFID tags that store only a serial number. I have seen more than 50 passive high-frequency (HF) and ultrahigh-frequency (UHF) tags read within a second. So the read time is mere milliseconds.
But the big advantage RFID offers over bar codes is that RFID does not require line of sight. So while RFID technology is slightly faster than scanning a bar code when you pick up a single tag and read it with a handheld, it is far faster when you perform inventory counts of multiple items on shelves or in a pile. That's because with a bar-code scanner, a person must orient the bar code to the scanner, while with RFID, you can just wave a scanner over the shelves and read all (or nearly all) tags on them.
To demonstrate this, RFID Journal provided a live demonstration in 2009 at an event in New York City. We placed 40 items on each of two racks, and asked people to take inventory with a bar-code scanner and a handheld RFID reader. If you watch the video (see RFID Put to the Test), you'll notice that 39 of the 40 tags were read in 12 seconds, while it took nearly 3 minutes to interrogate all of the bar codes. While the RFID reader missed only a single tag, the bar-code reader missed six. So RFID is 10 to 20 times faster than bar codes—and more accurate.
I should also point out that RFID tags and readers have improved since this demo was filmed, so you are more likely to obtain reads of all 40 tags in even less time.
—Mark Roberti, Founder and Editor, RFID Journal